Document Type


Publication Date


Publication Title

Parallel Processing Letters








We provide efficient parallel algorithms for the minimum separation, o ffset range, and optimal o ffset problems for single-layer channel routing. We consider all the variations of these problems that are known to have linear- time sequential solutions rather than limiting attention to the "river-routing" context, where single-sided connections are disallowed. For the minimum separation problem, we obtain O(lgN) time on a CREW PRAM or O(lgN / lglgN) time on a (common) CRCW PRAM, both with optimal work (processor- time product) of O(N), where N is the number of terminals. For the off set range problem, we obtain the same time and processor bounds as long as only one side of the channel contains single-sided nets. For the optimal o ffset problem with single-sided nets on one side of the channel, we obtain time O(lgN lglgN) on a CREW PRAM or O(lgN / lglgN) time on a CRCW PRAM with O(N lglgN) work. Not only does this improve on previous results for river routing, but we can obtain an even better time of O((lglgN)^2) on the CRCW PRAM in the river routing context. In addition, wherever our results allow a channel boundary to contain single-sided nets, the results also apply when that boundary is ragged and N incorporates the number of bendpoints.


Author Posting. © World Scientific Publishing, 1997. This is the author's version of the work. It is posted here by permission of World Scientific Publishing for personal use, not for redistribution. The definitive version was published in Ronald I. Greenberg, Shih-Chuan Hung, and Jau-Der Shih, Parallel Process. Lett. 07, 267 (1997).

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.